When starting hormonal contraception after POEC (Levonelle 1500® or Levonelle One Step®) additional contraception should be advised until contraceptive efficacy is established (see Summary on page iv). There are no data on quick starting hormonal contraception after use of the emergency contraceptive, ulipristal acetate (UPA) (ellaOne®). As UPA is a progesterone receptor modulator that blocks the action of progesterone, it may affect the contraceptive efficacy of hormonal However, no interaction studies have been carried out to date. Therefore, the CEU have taken a pragmatic approach in developing its recommendations and these may be amended if new evidence becomes available
